Such packagings are particularly manufactured from plastics. The lucent outer covering in connection with the inner reservoir arouses the optical impression of a particularly thick-walled glass reservoir, which, corresponding to a possibly different distance between the inner reservoir and the outer covering, seems to have different wall thicknesses resulting in a high-quality optical impression.
Conventionally, the manufacture of such packagings is extensive and costly, e.g. a manufacture by injection molding, a so-called insert technique, where the reservoir is blown, inserted in a mold and co-molded, or the manufacture of a compound created by ultrasound welding.